The county planning agency SANDAG is expected to make the final selection this morning on a route for the $1.2 billion extension of the San Diego Trolley north from Old Town to the UC San Diego campus and University Town Centre.

The new trolley route would extend the Blue Line 11 miles and is expected to be in operation in early 2015.

The anticipated decision by the SANDAG board of directors comes after several months of public comment on three possible alternative routes from which one has emerged as the preferred choice along what is known as the Mid-Coast Corridor.

The new rail line would go into the heart of a major employment and population center, second only in the county to downtown San Diego, where 25 percent of the people who work there take some kind of mass transit. A trolley to the Golden Triangle is expected to take off the road some of the 250,000 vehicles per day that clog Interstate 5.

A member of the group that studied the various routes, Anette Blatt, recently described the preferred trolley route’s other attractions. “This route will serve not only UCSD, but also other important employers like Scripps, Qualcomm and SAIC,” she said.

The new route has been endorsed by the Metropolitan Transit System, which operates the trolleys, and by numerous other planning and public agencies. In workshops and other sessions, the public too, has seemed to endorse this route over other proposals.

The board will be asked to consider one additional trolley stop today, according to SANDAG Executive Director Gary Gallegos. The recommendation to add a stop at the Veterans Hospital on the southeastern side of the UCSD campus grew out of the public comment sessions, he said.

For the Mid-Coast Corridor trolley, Gallegos sees a strong model in the Green Line, opened in 2005, which stops directly under San Diego State University. The Green Line’s 21,000 daily passengers far exceed ridership projections. The new Mid-Coast line is projected to attract 20,000 riders daily.

“Were trying to replicate that with Mid-Coast,” Gallegos said. “Get into the heart of the campus, taking transit right to where people want to go.”

UCSD-TV producer John Menier, a University Heights resident who has been making the daily drive up I-5 to the campus since 1997, thinks that’s the right strategy.

“I would love to take the trolley,” he said Thursday. There is always stress in commuting, he notes, as well as wear and tear on the vehicle and the cost of gas to consider. “Once on campus” he adds, “there is an enormous hassle in finding parking.”

Menier says the scarcity and cost of parking on campus is “argument enough for mass transit.”

While he couldn’t take the trolley every day because of the requirements of his work, Menier says he’d use it whenever his schedule and the trolley’s permitted it.

During five public meetings held in May and June on the several trolley routes under consideration, SANDAG reports that 700 comments were made by the 215 individuals attending. Only one was opposed specifically to the route expected to be approved.

There are other issues to be considered, said San Diegan Alan Hoffman, a transportation consultant. He declined to specifically address the SANDAG proposal but said that any decision “should look at where people actually are (in relation to a trolley line). How long does it take to get to your final destination in Mission Beach, Pacific Beach or La Jolla?”

Tracks for the new trolley line would be laid from Old Town to Gilman Drive, mostly within the transit right-of-way used by the Coaster commuter train, Amtrak and freight trains. Stops are planned at Tecolote Road, Clairemont Drive and Balboa Avenue.

At Gilman Drive, the trolley line would veer west of I-5, away from the train corridor, to a stop at Nobel Drive, followed by an on-campus stop near UCSD’s Price Center. At Voight Drive, the trolley would cross back over I-5, then cross Genesee Avenue before ending at a University Towne Center transit center.

Today’s board vote turns a corner on a proposal that has been around nearly as long as the 29-year-old trolley system. “It seems like a century ago that we first started talking about this line,” said county Supervisor Ron Roberts.

“I’ve been here about 20 years,” added SANDAG’s Gallegos, “and there has been talk of it for as long as I can remember.”

The next phase will be consumed with environmental impact studies, engineering designs and competition for as much as $600 million in federal funding to finance half of the trolley line construction. The other half will come from the TransNet fund, a half-cent sales tax long earmarked for the county’s transit needs.

That comes as a welcome relief to SANDAG’s Gallegos, who conveys a sense of urgency about the next phase.

“We’ve got half of the funds to do this,” he notes, “but we’re competing with others for the other half from the federal government. ... Many other regions are working on transit projects as the whole world tries to figure how to move smarter and cleaner.”

Said Gallegos: “There won’t be less competition for these dollars as time goes on. We want to get in (on the application process) as soon as we can.”